The remaining days before Christmas are likely to keep the U.S. retail sector busy, according to a Reuters/Ipsos poll of 1,330 U.S. adults, which found that only 18 percent had finished their holiday shopping, with 28 percent saying they had not started at all. All together, 58 percent of respondents said they had only completed half or less of their holiday shopping so far. Thomson Reuters analyst Jharonne Martis says the poll shows that the last two weeks before Christmas will be big for U.S. retailers, adding that the weekend of Dec. 22, “is going to be the pivotal sales weekend.” Expected spending also should be bolstered, compared to last year, by the extra two days between Thanksgiving and Christmas. Black Friday and Thanksgiving were a great success for retailers this year and Martis predicts that the biggest sales days are yet to come for retailers. Big-box retailers are expected to post a 5 percent rise in same-store sales this December, while department stores are likely to post a 4.5 percent gain.